Obsidian Therapeutics officially launched with the completion of a Series A financing worth $49.5 million. The company was founded in 2015 by Atlas Venture, who provided exclusive funding through mid-2017. The Series A was led by GV (formerly Google Ventures), with participation from AtlasVenture, Takeda Ventures, Vertex Ventures HC, Amgen Ventures, Alexandria Venture Investments, and ShangPharma Group.

Obsidian is focusing on immuno-oncology, and includes regulated cytokine cassettes to be used with CAR-T products. These enhance anti-tumor activity and cellular persistence, and provide regulated CAR-T cells to improve safety and anti-tumor efficacy. In this area, the company uses destabilizing domains (DD), which was developed by the Obsidian’s scientific founder, Thomas Wandless, a professor of Chemical and Systems Biology at Stanford University.

DD has two parts. One is a synthetic biological cassette. It is inserted in the gene vector. The second part is a small-molecule drug that controls the cassette. They are controlled with readily-available, non-immunosuppressive, FDA-approved small-molecule medicines.

The purpose of destabilizing domains is to help stabilize the fused payload protein in immuno-oncology therapeutics. When there is no specific small molecule ligand, fusion proteins degrade rapidly. But in the presence of the ligand, the fusion protein becomes stable and functional. Obsidian is working to engineer cells that have controllable functions that can be precisely tuned using already available non-immunosuppressive chemotherapy drugs.

“While existing cell therapies in oncology have shown substantial efficacy, the range of applications is still narrow, and significant toxicities limit broader adoption,” Gilman said in a statement. “By equipping cells with new tumor-fighting powers, and by putting precise and dynamic dosing control in the hands of the treating physician, we believe we can improve safety, efficacy, and durability of CAR-T therapies. Moreover, we think Obsidian’s pharmacologic operating systems will enable us to build entirely new classes of living medicines.”

The company licensed DD technology from Stanford University and launched a research collaboration with Crystal Mackall of the Stanford School of Medicine.

“The need for pharmacologic regulation in CAR-T is acute,” said Peter Barrett, partner at Atlas Venture and chairman of the board of Obsidian, in a statement. “We founded Obsidian to enable a new generation of cell therapies equipped with regulated cytokines, receptors, and transcription factors to give physicians and patients exquisite control over these powerful therapies.”